^$64i FOUilTH REPORT — lS3'i. 



in triple rows, those constituting the middle row are the most 

 perfect equilateral hexagons ; and those constituting the side 

 rows are partly polygonal and partly circular, similar in every 

 respect to those constituting the double rows. The corre- 

 sponding sides of the polygonal discs are generally connected 

 by two fine lines or fibres placed near the ends of each ; and 

 when the discs are well defined, they generally display concen- 

 tric circles in the interior, and two parallel straight lines corre- 

 sponding with the rectilinear boundaries of the polygonal kind. 

 The largest Araucarian discs are scarcely a quarter of the size 

 of the largest of those occurring in the true Pines. They are 

 so minute that to see them with advantage they should be mag- 

 nified four or five hundred times, and illumined by the light of 

 a snow-white cloud. 



On cutting longitudinal sections of various fossils parallel 

 to the partitions extending from the centre to the surface, discs 

 are often to be seen, resembling in every respect those occurring 

 in the Araucarian division of recent Coniferce. They occur in sin- 

 gle, double, triple, and sometimes even in quadruple rows. They 

 are sometimes circular, sometimes polygonal, at least in the 

 double and triple series, but in general the polygonal form pre- 

 dominates. When the arrangement is in the triple or quadruple 

 series, the discs in the middle row or rows are in general hexa- 

 gons, more or less regular; but in most specimens they are very 

 much obscured, and in many parts even completely obliterated. 

 In respect of size they are much smaller than those of the pine 

 division of coniferous fossils ; but they seldom or never display 

 more than the external bounding line, whether that line be cir- 

 cular or polygonal. 



Many examples of fossil Coniferce possessing discs similar to 

 those of the recent Aruucarite might here be adduced, but at pre- 

 sent it may suffice to notice three. Of these the fossil tribe at 

 present laid bare in Cragleith quarry first claims attention. In 

 that fossil the discs are in some parts entirely obliterated, but in 

 other parts, though much obscured, they are sufficiently obvious. 

 They are arranged in single, double, triple, and quadruple rows. 

 For the most part they are of a hexagonal form, and distinctly 

 alternate with each other. They merely retain the external 

 bounding line, and the vessels containing them are often very 

 much distorted. Their size is smaller than that of those of the 

 fossils belonging to the Pine division, but it is difficult to say 

 whether the double, triple, or quadruple series predominates. 

 One of the fossil Conifer fp from New Holland, contains discs 

 similar to those in the Cragleith tree, but much bolder, and 

 better defined. They are chiefly an-anged in single and double 



